Obesity: Disorders of Energy Balance

Obesity is defined as BMI > 95th percentile for age and sex. Overweight is defined as BMI of 85-95th percentile. Increasingly common in children (US prevalence 18.5% or ~ 13.7 million children and adolescents). Obesity is associated with risk for comorbidities that can persist into adulthood, such as diabetes mellitus, hypertension, early onset cardiovascular disease and osteoarthritis, dyslipidemia, precocious puberty, polycystic ovarian syndrome etc.

Etiology: most commonly exogenous (usually due to a combination of genetic predisposition and dietary/lifestyle habits). Other etiologies include drug-induced and endocrine-related. Genetic conditions associated with obesity include Prader-Willi Syndrome, Alstrom Syndrome, Bardet-Bied Syndrome, Down Syndrome, and Turner Syndrome. Endocrinopathies that can be associated with obesity include Cushing Syndrome and hypothalamic obesity and less likely growth hormone deficiency or hypothyroidism. Antidepressants, antiepileptics, glucocorticoids, and atypical antipsychotics are associated with an increased risk of obesity.

Diagnosis: Based on physical exam/ BMI. Screening for co-morbid conditions as sleep apnea, non-alcoholic fatty liver disease, type 2 diabetes, hypertension, dyslipidemia, or polycystic ovary syndrome is imperative.

Treatment: dietary/lifestyle changes to promote weight loss.   The only FDA approved medication for obesity in children less than 16 years of age is Orlistat but has unfavorable side effects, such as flatulence and oily, loose stools. Bariatric surgery can be considered for children with BMI greater than 40 kg/m2 with near-complete skeletal maturity.